Lubricating system for compressors



April 21, 1936. E, R A 2,038,131

LUBRIJGATINGY SYSTEM FOR COMPRESSORS Filed Aug. 19, 1955 2 Sheets-Sheetl' A INVENTOR William Edward Ric/10rd I BY" v ATTORNEY April 21, 1936.

W. E. RICHARD LUBRICATING SYSTEM FOR COMPRESSORS Filed Aug. 19, 1935 2Sheets-Sheet 2 INVENTOR Will/am Edward/iichard M ATTOR EY Patented Apr.21, 1936 UNITED STATES PATENT OFF-ICE This invention relates toimprovements in a lubricating system for compressors, and has for itsobject the provision of a lubricating system that will be simple andefflcient, which will sup- 5 .ply adequate lubrication to the workingparts of the compressor, its driving motor and the seal for the shaft ifone is used.

Other objects will be apparent from the following specification, theinvention consisting substantially in the construction, combination,location and relative arrangement of parts, all as will be more fullyhereinafter set forth, as shown by the accompanying drawings, and'finally pointed out in the appended claims. For the sake ofillustration, the invention will be described as applied to a compressorunit as commonly used in connection with refrigeration systems, such assmall motor driven household refrigerators. Such a unit is more fullydescribed in the copending application Serial No. 654,383, filed January31, 1 933, and entitled Refrigeration apparatus. It will be obvious,however, that the invention may be applied to any type of compressor orpump, or any other device having a shaft and bearings it is desired tolubricate, provided said device is capable of creating a suction orvacuum as hereinafter referred to.

In the accompanying drawings:

Figure 1 is a cross sectional view of a motorcompressor unit embodyingthe invention, of the type shown in the aforesaid copending applicationand having a seal about the driving shaft to prevent egressof fluid fromthe casing'through I which the shaft extends; and

Figure 2 is a vertical cross sectional view of a hermetically sealedmotor-compressor'unit embodying the invention, all working parts beingenclosed in a. hermetically sealed casing throughwhich the compressorshaft does not extend.

The construction of the motor-compressor units, Figures 1 and 2,v may bevaried within wide limits and consequently no detailed construction ofthe various parts is herein given exceptwhat is necessary to adequatelydescribe the lubricating system.

A motor-compressor unit commonly employed in connection -withrefrigeration systems such as that referred to in the aforesaidcopending application comprises a casing I!) having an inwardlyextending flange l'l adapted to support the compressor proper. Thecompressor may be of any suitable type, either rotary or reciprocating,and may consist of a body portion l2 having a. front end plate l3 and arear end plate l4 bolted thereon and enclosing the usual rotor,l5 whichis provided with shafts l6 and II. A cap -l8 encloses the bottom bearingas shown.

The end plate l3 when secured to the flange II by means of the bolts l9and 20 as shown, forms a top closure for the casing l8, and i3 and Hito- 5 gether define a closed chamber 2i containing a body of lubricant22 in which is immersed a tube 23 having a strainer'2 l on its outer endas shown. This tube communicates with a passage 25 in the end plate l4leading into the bearing supporting 10 shaft I]. The upwardly projectingshaft l8 has attached thereto and revolvable therewith a collar 26 whichhas secured thereto a sylphon bellows 21 which has secured to it thelower collar 28 which 15 is ground to seat and revolve upon a laterallyextending. flange 29 of the tubular member 38 which is supported in the.end plate l3.

Shaft I6 has secured to its outer end the nut 3| which supports themotor rotor '32, an outward 20 extension of this nut supporting thecooling fan 33. A flange 34 on the casing l0 supports the stator andwindings of the motor indicated by the numeral 35 which stator is heldin place by means of screws 350, as shown. The upper bearing 36 issupported in the tubular member 30. r The compressor is provided withthe usual inlet or suction-connection shown in dotted lines at 31 andthe pressure or discharge of the compressor passes into the passage 38in the body portion l2.

,The operation of the lubrication system will now be described. Assumingthat the compressor is connected into the refrigerating system and thatthe motor is operating and that asupply of 35 lubricant exists at 22 andthat the compressor is operating on any one of the well knownrefrigerants that may be used therewith which are taken into the suction31 in a more or less gaseous state, compressed and discharged; underthese 40 conditions the discharge at 38 is' comprised partly ofrefrigerant and partly of lubricant, and this mixture passes up passage38 and into passage 39 in the end plate 13 and into the annular cavity40 formed in the .end plate as shown and surrounding the tubular member30. The annular cavity 48 is sloped downwardly as shown so as to providea sump or pocket in which lubricant will collect, the lubricantseparating out of the gas- 0 eous mixture by gravity by reason of thewhirling 5 action that may be given the gas by properly sloping thepassage 39 as it enters the cavity 40 from the passage 38.

As the lubricant settles in 48 it enters the hole 4| in the tubularmember 38 and passes through the corresponding hole in the bearing 36,as shown, and into the interior annular groove in :lge bearing at thispoint, denoted by the numeral travels in two directions, first upwardlyalong the shaft l6 until it reaches the interior of the sylphon bellows21 and overflowing the top of bearing 36 the lubricant passes downthrough the annular space between the top of the bearing and theinterior of collar 28 and lubricates the ground sliding surfaces of thelower collar 28 and the flange 29 of the tubular member 30. Any excessof lubricant that finds its way to the interior of the sylphon passesdown the passage 43 which connects to the suction side of thecompressor. By the foregoing arrangement, the bearing 36 above theannular groove 42 is properly lubricated, as the lubricant is drawn outof the annular groove 42, up into the sylphon,'thereby lubricating theseal and is drawn down into the compressor and recirculated.

Secondly, the bearing is provided with another annular groove, as shownat 44, surrounding the shaft and communicating with the passage 43,through the hole 43a as shown in Fig. 1 and lubricant will be drawn downalong the shaft from the groove 42 and into the groove 44, the excessbeing drawn out into passage 43 and returned to the suction side of thecompressor and recirculated. This lower passage '44 therefore lubricatesthe bottom portion of the bearing 36. Compressed gases after leavingpart of the lubricant in the bottom of the annular cavity 40,

' pass downwardly through the passage 45 and out through the opening 46into the chamber 2| which puts a pressure on the lubricant 22 forcinglubricant through the strainer 24 into the tube 23 and through thepassage 25, thereby lubricating the bottom bearing for shaft l1.

The lubricant entering the compressor via pa'ssage 43 serves to seal andlubricate the same and thus all working parts of the compressor areproperly lubricated at all times.

It will be observed thatthe arrangement just described may be designedto provide a minimum pressure within the sylphon 21 so that a very lightspring 21a may be used to keep the lower collar 28 in tight sealingconnection with the flange 29.

The hermetically sealed unit shown in Figure 2 is of substantially thesame construction as that just described except that as no seal is used,the construction of the upper bearing is simplified.

In Figure 2, the compressor discharges into passages 38 and 39, aspreviously described, and

into the annular cavity 40. Lubricant settling in' the bottom of thiscavity runs down shaft l6 supported in the bearing 41, and finally findsits way into the annular space 48 surrounding the shaft which annularspace is connected via passage 49 with the'suction side of thecompressor. This insures the lubrication of the bearing 41.

The compressed gases leaving the annular cavity 40 pass down the passage45 and flnd egress at 46 into the chamber 2|. Part of these gases alsopass out of the hole at 45a into the upper chamber 2la of the interiorof the hermetically sealed unit so as to equalize the'pressure therein,it being understood that the upper chamber 2la is at the same pressureat all times as the chamber 2|.

A cap 50 is provided above the annular cavity 40. This cap is a runningfit on the shaft It. It merely prevents the constant escape of a largequantity of mixture at this point. It does not From this'annular groove,the lubricant act as a gas tight seal, for the reason that in theconstruction shown in Figure 2, the casing I0 is provided with an uppercasing 5| joined thereto by bolts 52, whereby all parts are hermeticallysealed, the only openings being for the inlet pipe to the compressor andthe outlet for the compressed gases communicating with the chamber 2|.

For the sake of illustration, machines have been shown in which theshafts are vertical, but the system of lubrication may be applied to amachine in which the shafts are horizontal, in-

would lie in a plane at right angles to the shaft either in front orback thereof, finally connecting with the outlet 46. As suchmodifications are obvious to one skilled in they art, they are not hereshown nor described in detail.

Although the invention has been disclosed in connection with specificdetails of preferred embodiments thereof, it must be understood thatsuch details are not intended to be limitative of the invention exceptin so far as set forth in the accompanying claims.

What is claimed is:

1. In apparatus of the class described, a casin a shaft projecting fromsaid casing, a seal about said shaft wherebythe latter is .maintained influid tight relation to said casing, a compressor having a suction inletand a discharge outlet, a chamber adjacent said shaft communicatingdirectly within the casing with said outlet, a bearing for said shaft, apassage between said chamber and the interior of said bearing wherebylubricant may pass from said chamber into said bearing and lubricate thesame, a passage communicating with the interior of said seal and saidinlet whereby excess lubricant entering the interior of said seal willbe drawn into said compressor, and an annular groove about said shaftconnected to the suction side of said compressor whereby lubricant willbe drawn along said shaftfrom said first chamber into said groovethereby lubricating the shaft.

2. In apparatus of the class described, a casing, a compressor having anend plate supported on said casing and forming therewith a. chamberadapted to enclose lubricant, a shaft for driving said compressorextending outward through the end plate thereof, a tubular membermounted in said end plate and having a flange extending lat- 'erallytherefrom, sealing means carried on said groove connected to the suctionside of'said compressor whereby lubricant may be drawn from said groovealong said shaft and into said sealing means to lubricate the same andalong said shaft in an opposite direction to lubricate the same. r

3. In apparatus of the class described, a'caslng enclosing a body oflubricant, a compressor having a shaftand bearings and adapted todischarge above said lubricant and thereby apply pressure thereto, saidcompressor having a suction intake extending outside said casing, meansfor admitting lubricant under the aforesaid pressure to one of thebearings of said compressor, and means for collecting lubricant from thedischarge of said compressor before said discharge enters said casingand applying said collected lubricant to a bearing of said compressor,said means including a member having an annular space thereinsurrounding the bearing and connected to the suction-side of thecompressor whereby lubricant is drawn along the compressor shaft fromsaid lubricant collecting means into said annular space therebylubricating the bearing.

4. In apparatus of the class described, a compressor having a shaft anda bearing therefor, means including a-sump directly surrounding saidshaft and in direct fluid communication therewith and with said bearinginto which said compressor discharges, for applying lubricant to saidbearing, said bearing having an annular interior groove surrounding saidshaft and in fluid communication with the suction side of saidcompressor whereby lubricant may be drawn from said sump along saidshaft thereby lubricating the same, a discharge duct connected to saidsump adapted to deliver excess lubricant to a point below said annularinterior groove, and a body of of lubricant separate from said sump forsupplying same with lubricant.

5. In apparatus of the class described, a casing adapted to hold a bodyof lubricant under pressure, a compressor in said casing having a shaft,

a member forming a sump adapted to receive lubricant and positionedabout said bearing and shaft, a passage between the discharge outlet ofsaid compressor and said sump whereby all of thedischarge. includinglubricant from the compressor is conveyed to said sump and lubricantaccumulates therein, a passage from said sump to the space within saidcasing above said body of lubricant, and a bearing for said shaft havingan annular cutaway portion surrounding the shaft and connected to thesuction side of the compressor whereby lubricant may be withdrawn fromsaid sump along said shaft and into said cutaway portion, therebylubricating said bearing.

6. In apparatus of the class described, a casing adapted to holdlubricant under pressure, a compressor in said casing having astationary body portion, front and rear endplates connected to said bodyportion, bearings in said end plates, a shaft for said compressor,passages in said body portion and front end plate whereby all of thedischarge from said compressor is conducted to the outer end of thebearing therein, means whereby lubricant discharged at the outer end ofsaid frontbearing may be drawn therethr'ol'igh casing, and means forsupplying said last lubricant to the bearing in the rear end plate ofsaid compressor.

WILLIAM EDWARD RICHARD.

